The question is incomplete, the complete question is;
Arrange the following ionic compounds in order of decreasing amount of energy released in lattice formation: NaF, MgS, TlN, and CsI.
Answer:
TlN> MgS > NaF > CsI
Step-by-step explanation:
Recall that lattice energy is the energy evolved when a crystal lattice is formed from its component ions.
The lattice energy depends on the size of the ions. The smaller the sizes of the ions, the larger the lattice energy.
The order of energy released in lattice formation for these compounds is;
TlN> MgS > NaF > CsI